continued reorganisation

bcrypter/cli/repl.py

@@ -0,0 +1,42 @@
+import readline # GNU readline (ie allows input() history buffer)
+from itertools import chain
+
+from bcrypter.cli.builtins import *
+from bcrypter.cli.commands import *
+from bcrypter.lib.result import Result
+from bcrypter.exceptions import CmdDeclarationError
+
+class REPL:
+    _PROMPT = '>> '
+    _DEFAULT_HISTORY_FILE = '.bcrypter_history'
+
+    _BUILTINS = [
+        BuiltinHelp(),
+    ]
+    _COMMANDS = [
+    ]
+    
+    def __init__(self, history_file: str = _DEFAULT_HISTORY_FILE) -> None:
+        for cmd in chain(REPL._BUILTINS, REPL._COMMANDS):
+            result = cmd._is_consistent():
+            if result.is_err():
+                raise CmdDeclarationError(result.message)
+        self._history_file = history_file
+        readline.read_history_file(self._history_file)
+
+    def __del__(self) -> None:
+        readline.write_history_file(self._history_file)
+
+    def prompt(self) -> str:
+        return input(REPL._PROMPT)
+
+    '''
+    Parse and execute a string command
+    '''
+    def exec(self, cmd: str) -> Result[Command]:
+        cmd = cmd.strip().split()
+        if not len(cmd):
+            return Result.warn('No command given')
+        
+            
+